The present invention relates to rail retaining devices for incorporation in a rail track.
The invention provides a rail retaining device comprising a shoulder member for bearing on a lateral side of a rail flange, and providing a downwardly facing abutment surface, and a rail clip in the form of a bent rod symmetrical about a vertical plane for extending laterally of the rail and having an inner portion for bearing on an adjacent flange in an installed position, intermediate limb portions for bearing upwardly on the downwardly facing abutment surface, and an outer portion connected to each intermediate limb portion for extending outwardly from said abutment surface and curving laterally arcuately outwardly and downwardly toward a lower portion adapted to bear on a bearing surface, and wherein in said installed position there is a reaction between the intermediate limb portions and the downwardly forcing abutment surface flexing the intermediate limb portions resiliently downwardly.
The arrangement of the invention provides excellent stress distribution and avoids stress concentrations that can contribute to premature failure in known clips. Further, the clip is compliant and tolerant of dimensional variation in the components and is relatively easily to install, while providing a highly effective and durable rail retaining function.
Preferably, the lower portion of the clip is adapted to bear on a bearing surface at a region that is offset laterally inwardly from a centre of curvature of the outer portion. This further improves the stress distribution through the clip in service.
In a preferred form, the inner portion comprises an upwardly bowed portion adjacent the abutment surface that provides increased resistance to migration of the clip outwardly from its installed position as a result of impacts or vibration encountered in service.
Preferably, each lower portion of said outer portions inclines longitudinally with respect to said vertical plane, whereby squatting of the outer portion is facilitated during installation, rendering the clip particularly compliant and facilitating installation.